This project emphasizes studies using newly emerging robust non invasive ultrasonic imaging technologies for quantifying structural and functional cardiovascular pathology. Using hydrodynamic principles, temporal and spatial aspects of cardiac structural abnormalities and pathophysiologic flow events are described and their quantification validated. In the clinical management of cardiac dysfunction, quantitatively accurate assessment is of major importance for diagnosis, prognosis and therapy. Non invasive assessment is, in addition, economically desirable. To these ends, the current year's efforts have extended previous years' studies to include: 1) real-time, three-dimensional (i.e. four-dimensional) echocardiography for determining right ventricular stroke volume in the presence of right ventricular volume overload; 2) direct measurement of three-dimensionally reconstructed flow convergence isovelocity surface area for quantifying aortic regurgitant flow; 3) vena contracta imaged by Doppler color flow mapping for predicting the severity of mitral regurgitation; 4) imaging the vena contracta by color Doppler for quantifying aortic regurgitation; 5) the use of digital color Doppler flow mapping for calculating aortic regurgitant volume and 6) estimating aortic regurgitant effective orifice area by digital Doppler color flow mapping. Similar studies are on-going using animal models of coronary artery disease. These studies have direct clinical relevance and applicability.